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034 How Lateral Inhibition Enhances Visual Edges

In this video, Leslie explains all about lateral inhibition using two rectangles. Watch to learn how this process helps us see edges of objects more clearly. Enjoy!

 

Transcript of Today’s Episode

Welcome to another episode of Interactive Biology TV, where we’re making biology fun! My name is Leslie Samuel. In this episode, Episode 34, I’m going to talk about how lateral inhibition enhances visual edges. What am I talking about? Well, you’re going to see right now.

Here, we have 2 rectangles. One is darker and the other is lighter. It’s just a solid gray color over here, and a solid darker gray, almost black color, over here. What I’m going to do is I’m going to show you something that’s quite fascinating, at least it’s fascinating to me. It illustrates how visual processing can lead to some interesting things. To a certain extent, it shows that what you see is not always what’s there.

What am I talking about? Well, what I’m going to do is I’m going to take this gray rectangle over here and I’m basically going to move it towards the other one. We’re going to see what happens. Remember it’s a solid gray color, the same color that I have over here, it’s the same color that I have over here, and throughout the entire rectangle. Now let’s put them together and see if anything happens. So I’m just going to move the one on the right towards the one at the left. And now, hopefully you can see this, depending on the monitor that you’re using, you may or may not be able to see this, but I’m guessing you will be able to see it.

What you’re going to notice here is right here at the border, you’re going to see that here is just a little lighter than over here. So before, it looked like a solid gray object, and I really hope you see this, or else this is pointless, and over here now, we’re seeing that it’s darker here than it is over here. If you don’t see it, look closely at the monitor and see if you see a little bit of a lighter edge here.

Now, is that lighter edge there? No, it really isn’t. But there’s something that’s happening inside your eye that’s making it seem as if it’s lighter over here and a little darker over here, you might be able to see that also. So, lighter on this side, and darker on this side, just a little bit. What we’re going to do is look at why that’s the case.

The main idea, though, is that the brain is set up to enhance visual edges so that you can see the edges more clearly. I find this to be very fascinating because to me, it illustrates that maybe what we see might not actually be what is there. And I don’t know how much that extends into everyday life, but it’s an interesting concept nonetheless. Now, let’s look at the cells that we have in the retina.

We looked at this already. We said that here we have the rods and this would be a cone, we said that here we have a horizontal cell, and here we have ganglion cells, and we also have amacrine cells. This is just a review of an earlier episode. The cell that I’m most concerned with now in terms of this process is the horizontal cell. You can see here, we have a number of rods, and we have a cone, and this horizontal cell goes laterally, and it connects to multiple rods and even connects to some of the cones. This is where the processing that enhances those visual edges starts.

So it’s happening in the retina, this entire thing is in the retina. What happens is if it’s getting a lot of intense stimulation from a group of rods over here, that causes this horizontal cell to inhibit some of the other cells so you do not get as much stimulation from those receptors that are not stimulated as intensely as these over here. So we have a strong stimulation coming via these rods or these receptor cells, and that’s causing inhibition of some of the cells that are not being stimulated as much. This process is called lateral inhibition, and to me it’s a very fascinating concept, showing that strong activity over here can inhibit activity in another area.

That’s all I want to cover in this episode. That’s it for this video. If you have any questions or comments, go ahead and leave them below, and I’ll be happy to take a look at them, and maybe even answer the questions that you might have. That’s all for now, and I’ll see you in the next video.

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Leslie Samuel is the creator of Interactive Biology. His mission is to use this site to Make Biology fun for people all over the world.

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Leave An AWESOME Comment

92 Responses to “034 How Lateral Inhibition Enhances Visual Edges”

  1. dmblax10 February 23, 2011 at 10:06 pm #

    great video – definitely made things much clearer

  2. Chris Koller February 23, 2011 at 10:06 pm #

    great video – definitely made things much clearer

  3. InteractiveBiology February 23, 2011 at 10:08 pm #

    @dmblax10 Glad to hear. Make sure to stay tuned because there’s lots more to come :)

  4. InteractiveBiology February 23, 2011 at 10:08 pm #

    Glad to hear. Make sure to stay tuned because there’s lots more to come :)

  5. InteractiveBiology February 23, 2011 at 10:08 pm #

    @dmblax10 Glad to hear. Make sure to stay tuned because there’s lots more
    to come :)

  6. actos386 March 11, 2011 at 7:24 pm #

    Hello, I want to let you know that I love your job, because it gives me a 3D vision of what I´m studyng, so don´t be surprised if you see that I like all your videos.
    What I want to ask you is about your bibliography. You see, my teacher is really strict when it comes to that point, he wants us to get the best info, and the last editions.
    Other question is: do you know any information about the bipolar receptors and the cones and rodes neurotransmitters?

  7. actos386 March 11, 2011 at 7:24 pm #

    Hello, I want to let you know that I love your job, because it gives me a 3D vision of what I´m studyng, so don´t be surprised if you see that I like all your videos.
    What I want to ask you is about your bibliography. You see, my teacher is really strict when it comes to that point, he wants us to get the best info, and the last editions.
    Other question is: do you know any information about the bipolar receptors and the cones and rodes neurotransmitters?

  8. actos386 March 11, 2011 at 7:24 pm #

    Hello, I want to let you know that I love your job, because it gives me a
    3D vision of what I´m studyng, so don´t be surprised if you see that I like
    all your videos. What I want to ask you is about your bibliography. You
    see, my teacher is really strict when it comes to that point, he wants us
    to get the best info, and the last editions. Other question is: do you know
    any information about the bipolar receptors and the cones and rodes
    neurotransmitters?

  9. actos386 March 11, 2011 at 7:32 pm #

    Hello again
    I forgot to tell you: keep doing this! you are helping a lot of people. This is the future of studying. Im not saying that I dont beleieve in classes, I love the. I also think books are really important, but this can really clear my mind when I see how exactly the proccess happens.
    Thanks!!!

  10. actos386 March 11, 2011 at 7:32 pm #

    Hello again
    I forgot to tell you: keep doing this! you are helping a lot of people. This is the future of studying. Im not saying that I dont beleieve in classes, I love the. I also think books are really important, but this can really clear my mind when I see how exactly the proccess happens.
    Thanks!!!

  11. actos386 March 11, 2011 at 7:32 pm #

    Hello again I forgot to tell you: keep doing this! you are helping a lot of
    people. This is the future of studying. Im not saying that I dont beleieve
    in classes, I love the. I also think books are really important, but this
    can really clear my mind when I see how exactly the proccess happens.
    Thanks!!!

  12. InteractiveBiology March 12, 2011 at 6:51 pm #

    @actos386 Thank you so much for your kind words. I’m glad you’re finding value in the content of this video.

    In terms of the bibliography, yes that is very important when you are publishing stuff. You want to give credit where credit is due. I don’t post a bibliography on these videos because these are all from my notes I took when I was in college.

    Yes, I do have info on bipolar cells in the visual cortex. They are explained in episode 35 of my videos. Check it out.

  13. InteractiveBiology March 12, 2011 at 6:51 pm #

    Thank you so much for your kind words. I’m glad you’re finding value in the content of this video.

    In terms of the bibliography, yes that is very important when you are publishing stuff. You want to give credit where credit is due. I don’t post a bibliography on these videos because these are all from my notes I took when I was in college.

    Yes, I do have info on bipolar cells in the visual cortex. They are explained in episode 35 of my videos. Check it out.

  14. InteractiveBiology March 12, 2011 at 6:51 pm #

    @actos386 Thank you so much for your kind words. I’m glad you’re finding
    value in the content of this video. In terms of the bibliography, yes that
    is very important when you are publishing stuff. You want to give credit
    where credit is due. I don’t post a bibliography on these videos because
    these are all from my notes I took when I was in college. Yes, I do have
    info on bipolar cells in the visual cortex. They are explained in episode
    35 of my videos. Check it out.

  15. InteractiveBiology March 12, 2011 at 6:52 pm #

    @actos386 Thank you again. I do agree that the internet will play a MAJOR role in how education happens. More and more people are going to have access to this type of knowledge as technology advances and people are able to access this type of info from anywhere.

    Thank you for the encouragement!

  16. InteractiveBiology March 12, 2011 at 6:52 pm #

    Thank you again. I do agree that the internet will play a MAJOR role in how education happens. More and more people are going to have access to this type of knowledge as technology advances and people are able to access this type of info from anywhere.

    Thank you for the encouragement!

  17. NikkiGeo11 April 19, 2011 at 6:39 am #

    all of this is great! after hours of reading on this, i finally get it in just one hour of watching your video!!

  18. Nikki Georgiou April 19, 2011 at 6:39 am #

    all of this is great! after hours of reading on this, i finally get it in
    just one hour of watching your video!!

  19. InteractiveBiology April 19, 2011 at 9:44 am #

    @NikkiGeo11 That’s awesome to hear. Glad it has helped you so much. There are many more coming :)

  20. InteractiveBiology April 19, 2011 at 9:44 am #

    That’s awesome to hear. Glad it has helped you so much. There are many more coming :)

  21. InteractiveBiology April 19, 2011 at 1:44 pm #

    That’s awesome to hear. Glad it has helped you so much. There are many more coming :)

  22. renrocks27 May 15, 2011 at 4:42 am #

    @NikkiGeo11 Im with Nikki on this.. fantastic work thanks so much!

  23. renrocks27 May 15, 2011 at 4:42 am #

    Im with Nikki on this.. fantastic work thanks so much!

  24. renrocks27 May 15, 2011 at 8:42 am #

    Im with Nikki on this.. fantastic work thanks so much!

  25. megaapfel May 23, 2011 at 8:45 pm #

    thank you so much for this video! Greetings from germany :)

  26. InteractiveBiology May 23, 2011 at 9:56 pm #

    @megaapfel You are very much welcome. Thanks for your comment from Germany :)

  27. InteractiveBiology May 23, 2011 at 9:56 pm #

    You are very much welcome. Thanks for your comment from Germany :)

  28. megaapfel May 24, 2011 at 12:45 am #

    thank you so much for this video! Greetings from germany :)

  29. InteractiveBiology May 24, 2011 at 1:56 am #

    You are very much welcome. Thanks for your comment from Germany :)

  30. tryhardgirl June 18, 2011 at 5:33 am #

    you are amazing

  31. tryhardgirl June 18, 2011 at 9:33 am #

    you are amazing

  32. InteractiveBiology July 25, 2011 at 9:58 pm #

    @Mansuya Wow, thanks for your comment. Those kinds of comments give me the motivation I need to continue making these videos.

    All the best!

  33. InteractiveBiology July 25, 2011 at 9:59 pm #

    @Mansuya If you watch the video again, you will see an example of what I mean. When I put the two rectangles together, you should see one becoming lighter. Watch it carefully.

  34. InteractiveBiology July 26, 2011 at 1:58 am #

    @Mansuya Wow, thanks for your comment. Those kinds of comments give me the motivation I need to continue making these videos.

    All the best!

  35. InteractiveBiology July 26, 2011 at 1:59 am #

    @Mansuya If you watch the video again, you will see an example of what I mean. When I put the two rectangles together, you should see one becoming lighter. Watch it carefully.

  36. Bas September 7, 2011 at 5:10 pm #

    Hello, can i see this as a sort of cross-over distortion like in a stereo
    audio amplifier when the signal of one channel is picktup by the other?

    • Lrsamuel September 7, 2011 at 6:45 pm #

      Never thought of it that way, but I guess you can compare it to that somewhat. It is similar in some ways.

  37. youremocional September 22, 2011 at 7:31 pm #

    When you said than the horizontal cell is inhibiting the cones or rods, what neurotransmisor is acting???…

  38. InteractiveBiology September 22, 2011 at 11:20 pm #

    @youremocional All questions are answered in the Interactive Biology community forums from now on. Go to the website in the description and then visit the community. This is to make it as efficient as possible as we have multiple people over there to help answer questions.

    All the best

  39. youremocional September 22, 2011 at 11:31 pm #

    When you said than the horizontal cell is inhibiting the cones or rods, what neurotransmisor is acting???…

  40. InteractiveBiology September 23, 2011 at 3:20 am #

    All questions are answered in the Interactive Biology community forums from now on. Go to the website in the description and then visit the community. This is to make it as efficient as possible as we have multiple people over there to help answer questions.

    All the best

  41. Bpatel8519 October 10, 2011 at 3:59 am #

    You are excellent. This helped me out so much for my Physiological Psychology exam. Thanks!

  42. Bpatel8519 October 10, 2011 at 3:59 am #

    You are excellent. This helped me out so much for my Physiological Psychology exam. Thanks!

  43. InteractiveBiology October 10, 2011 at 5:38 am #

    @Bpatel8519 Great to hear. Thanks for the feedback. Stay tuned for more!

  44. InteractiveBiology October 10, 2011 at 5:38 am #

    Great to hear. Thanks for the feedback. Stay tuned for more!

  45. Bpatel8519 October 10, 2011 at 7:59 am #

    You are excellent. This helped me out so much for my Physiological Psychology exam. Thanks!

  46. InteractiveBiology October 10, 2011 at 9:38 am #

    Great to hear. Thanks for the feedback. Stay tuned for more!

  47. zusamin1 October 15, 2011 at 8:25 pm #

    lighter becomes lighter. darker becomes darker. darker side gets more inhibted as it is less stimulated than the lighter side.
    But why the edge on darker side looks even darker? more inhibition reached to the edge than the far end?
    Lighter side looks lighter in the edge why? are there inhibition to the non-edge side of the lighter side? why?
    Is there selective inhibition to cons and rods?
    im so confused :s

  48. InteractiveBiology October 15, 2011 at 8:32 pm #

    @zusamin1 All questions are answered in the Interactive Biology community forums from now on. Go to the website in the description and then visit the community. This is to make it as efficient as possible as we have multiple people over there to help answer questions.

    All the best

  49. zusamin1 October 16, 2011 at 12:25 am #

    lighter becomes lighter. darker becomes darker. darker side gets more inhibted as it is less stimulated than the lighter side.
    But why the edge on darker side looks even darker? more inhibition reached to the edge than the far end?
    Lighter side looks lighter in the edge why? are there inhibition to the non-edge side of the lighter side? why?
    Is there selective inhibition to cons and rods?
    im so confused :s

  50. InteractiveBiology October 16, 2011 at 12:32 am #

    All questions are answered in the Interactive Biology community forums from now on. Go to the website in the description and then visit the community. This is to make it as efficient as possible as we have multiple people over there to help answer questions.

    All the best

  51. pfshepherd2010 December 11, 2011 at 8:38 am #

    Is it bad if I don’t see the lighter edge when you combine the two shades of gray? I am using a 1080p, 120hz, 22inch computer monitor and full screen 720p hd video stream. I don’t see it. I have looked at other pictures and videos that demonstrate this concept and I still don’t see but my friend does. What does this mean about my eyes? Am I going color blind?

  52. pfshepherd2010 December 11, 2011 at 8:38 am #

    Is it bad if I don’t see the lighter edge when you combine the two shades of gray? I am using a 1080p, 120hz, 22inch computer monitor and full screen 720p hd video stream. I don’t see it. I have looked at other pictures and videos that demonstrate this concept and I still don’t see but my friend does. What does this mean about my eyes? Am I going color blind?

  53. InteractiveBiology December 11, 2011 at 8:45 am #

    @pfshepherd2010 Unfortunately, Leslie has a lot of work to do right now to be able to attend to the number of emails he’s been receiving lately. I would strongly suggest though that you go and see an eye doctor about your observations just to be sure. We hope it’s nothing that complicated… Do take care!

  54. InteractiveBiology December 11, 2011 at 8:45 am #

    Unfortunately, Leslie has a lot of work to do right now to be able to attend to the number of emails he’s been receiving lately. I would strongly suggest though that you go and see an eye doctor about your observations just to be sure. We hope it’s nothing that complicated… Do take care!

  55. pfshepherd2010 December 11, 2011 at 1:38 pm #

    Is it bad if I don’t see the lighter edge when you combine the two shades of gray? I am using a 1080p, 120hz, 22inch computer monitor and full screen 720p hd video stream. I don’t see it. I have looked at other pictures and videos that demonstrate this concept and I still don’t see but my friend does. What does this mean about my eyes? Am I going color blind?

  56. InteractiveBiology December 11, 2011 at 1:45 pm #

    Unfortunately, Leslie has a lot of work to do right now to be able to attend to the number of emails he’s been receiving lately. I would strongly suggest though that you go and see an eye doctor about your observations just to be sure. We hope it’s nothing that complicated… Do take care!

  57. bigdaddykenkuo February 11, 2012 at 9:31 pm #

    This video is incredibly resourceful. I’m using this to study for my Behavioral Neuroscience Exam. Thank you, and I like your accent.

  58. bigdaddykenkuo February 12, 2012 at 2:31 am #

    This video is incredibly resourceful. I’m using this to study for my Behavioral Neuroscience Exam. Thank you, and I like your accent.

  59. Yvonne February 27, 2012 at 2:04 pm #

    Thank you so much for posting the video’s on the Special Senses! We have a test on Tuesday and your video’s always make things clear to me.

  60. shoutatthesky March 22, 2012 at 1:29 am #

    I don’t see it either. When I first heard about lateral inhibition I was blown away. This video does not describe it well. I don’t think there is anything wrong with your eyes just this person’s description of the concept.

  61. shoutatthesky March 22, 2012 at 5:29 am #

    I don’t see it either. When I first heard about lateral inhibition I was blown away. This video does not describe it well. I don’t think there is anything wrong with your eyes just this person’s description of the concept.

  62. kboci88 April 23, 2012 at 2:37 pm #

    5 hours of reading and messing up concepts got clear in 5 minutes!thx!

  63. kboci88 April 23, 2012 at 2:37 pm #

    5 hours of reading and messing up concepts got clear in 5 minutes!thx!

  64. kboci88 April 23, 2012 at 6:37 pm #

    5 hours of reading and messing up concepts got clear in 5 minutes!thx!

  65. ilikephilipp May 6, 2012 at 12:01 pm #

    Not necessarily. I couldn’t see it at all, at first. The two rectangles are diffferent colors (you do see that part, right?). One is grey (on the right), the other is dark grey (to me, it looks black). When Leslie brought the two rectangles in contact, the thing I can see clearly is that they are, in fact, different colors. One is darker, (left one), one is lighter (right one). The thin strip Leslie is talking about is very small, and’s at the very edge of the border between the two rectangles.

  66. ilikephilipp May 6, 2012 at 12:01 pm #

    Not necessarily. I couldn’t see it at all, at first. The two rectangles are diffferent colors (you do see that part, right?). One is grey (on the right), the other is dark grey (to me, it looks black). When Leslie brought the two rectangles in contact, the thing I can see clearly is that they are, in fact, different colors. One is darker, (left one), one is lighter (right one). The thin strip Leslie is talking about is very small, and’s at the very edge of the border between the two rectangles.

  67. ilikephilipp May 6, 2012 at 12:03 pm #

    It doesn’t even look like a lighter border — the definition is very faint, and my brain is overriding it by telling me that it is just the two rectangles. This might be the case with you, as well. The border IS very fine — more of a shimmering at the edge, than a real color difference — it’s just a minor detail, one of those blink-it-and-you’ll-miss-it, kind of things.

  68. ilikephilipp May 6, 2012 at 12:03 pm #

    It doesn’t even look like a lighter border — the definition is very faint, and my brain is overriding it by telling me that it is just the two rectangles. This might be the case with you, as well. The border IS very fine — more of a shimmering at the edge, than a real color difference — it’s just a minor detail, one of those blink-it-and-you’ll-miss-it, kind of things.

  69. ilikephilipp May 6, 2012 at 12:04 pm #

    Comment was too long. Read my comment entitled “Not necessarily” first, then the “It doesn’t…” one.

    Best of luck to you!

  70. ilikephilipp May 6, 2012 at 12:04 pm #

    Comment was too long. Read my comment entitled “Not necessarily” first, then the “It doesn’t…” one.

    Best of luck to you!

  71. slashmasteryo May 14, 2012 at 11:45 am #

    Nice Video, your stuff is helping me while learning for my german oral exam tomorrow. Thanks!

  72. slashmasteryo May 14, 2012 at 11:45 am #

    Nice Video, your stuff is helping me while learning for my german oral exam tomorrow. Thanks!

  73. eternalrecreation May 31, 2012 at 1:13 pm #

    cool. it took me a while to see, but i saw!

  74. eternalrecreation May 31, 2012 at 1:13 pm #

    cool. it took me a while to see, but i saw!

  75. eternalrecreation May 31, 2012 at 1:13 pm #

    cool. it took me a while to see, but i saw!

  76. SuperBipul12345 June 15, 2012 at 5:09 pm #

    photoshopped just kidding

  77. SuperBipul12345 June 15, 2012 at 5:09 pm #

    photoshopped just kidding

  78. slothobsessed June 18, 2012 at 7:19 am #

    is there a video on population coding? or maybe are you able to quickly just explain it?
    Cheers

  79. slothobsessed June 18, 2012 at 7:19 am #

    is there a video on population coding? or maybe are you able to quickly just explain it?
    Cheers

  80. karismamac September 5, 2012 at 12:39 am #

    This was very helpful! Especially the visual aid! Understand it a whole lot better now! XD Thanks!

  81. soska doll October 12, 2012 at 9:53 am #

    … very helpful
    thaaaaaaaaaanks

  82. soska doll October 12, 2012 at 10:23 am #

    very helpful !
    thaaaaaaaaaaaanks :)

  83. SuperMonster62 November 30, 2012 at 10:16 am #

    Great vid!!!!

  84. SuperMonster62 November 30, 2012 at 10:18 am #

    And I can even see the lighter area on my phone lol

  85. Papiertierchen January 29, 2013 at 7:11 pm #

    Thank you for that vid :)

  86. WhimsicalEccentrics April 11, 2013 at 10:28 pm #

    Thank You! You cleared up what I spent hours trying to figure out in under five minutes!

  87. Hordkorowiec328 April 17, 2013 at 9:02 pm #

    Could someone give a link to that community forums? I couldn’t find it on IB site :-/. And I am too a bit confused. Inhibition coming out from more stimulated cells (light color) would result in dark color being perceived as even darker near the edge. I, however, see area around the black figure as somewhat lighter so there has to be extra stimulation going on. However, I guess that the point of the video was to give a general idea how it works (Ie, that it happens in retina – not in brain)

  88. Michael McPartlin May 8, 2013 at 3:19 pm #

    Videos are great. The voice is very easy to listen to and the content is correct. Unfortunately, I am unable to see the gradient in color once the black and grey box meet. I am unsure of whether or not my monitor is bad or my eyes are bad. Either way, thanks for the content.

  89. linux vps August 5, 2013 at 7:15 am #

    What a material of un-ambiguity and preserveness of valuable familiarity on the topic of unexpected feelings.|

  90. GBuckne August 9, 2013 at 10:15 pm #

    At first I didn’t see it, but finally noticed a darker and lighter line about 1/32 of an inch.

  91. Rich White November 3, 2013 at 3:03 am #